Slitters | Safeguarding for Specific Types of Machinery

Slitters use rotary knives to slit flat rolled metal, plastic film, paper, plastic, foam, and rubber as well as other coiled or sheet fed materials. Slitters range from small hand-fed paper slitters to large-scale automated metal slitters, complete with metal processing and handling units such as unwinders and rewinders. Both light and heavy gage slitters are available.

Slitter hazards

Amputations often occur when clothing or body parts come in contact with slitter blades or get caught in the movement of coils and rolls. Here are some example:

§  Workers can inadvertently get their fingers and hands caught in the in-going nip points of the slitter or associated machinery such as rewinders.

§  Gloves, jewelry, and loose clothing can get entangled in in-going nip points or in the rotary knives of the slitter.

§  Workers can suffer an amputation when clearing, adjusting, cleaning, or servicing the slitter while it is either still operating, or shut off but still plugged in (energized).

Case History

An employee was feeding cardboard strips onto slit steel as it was being coiled on a slitter machine. While the machine was operating, the employee was placing the cardboard strips on the coils. After reaching over the steel strips, the coiled steel on the mandrel pulled his right arm into the machine and amputated it. Source: OSHA IMIS Accident Investigation Database

Slitter machine safeguards

You can use guards and other engineering controls such as the following:

§  Install a fixed or adjustable point of operation guard at the in-feed and out-feed section of the machine.

§  Install a fixed point of operation guard to cover the sides of the unwinder/rewinder to prevent an employee’s hands or clothing from entering into the rollers.

§  Install fixed or interlocked guards to cover other moving parts of the machine such as the power transmission apparatus.

§  Use an awareness barrier guard with an interlocking gate around the perimeter of the machine to prevent unauthorized entry.

§  Provide guards for operator control stations to prevent inadvertent activation.

Work practice and administrative controls

You can also implement work practices and administrative controls to help do the following:

§  Develop and implement safe work procedures for machine operators and conduct periodic inspections to ensure compliance.

§  Ensure that all operators receive appropriate on-the-job training and supervision until they can work safely on their own.

§  Instruct employees to perform servicing and maintenance activities under an energy control program in §1910.147.

Grinding machines | Safeguarding for Specific Types of Machinery

Grinding machines primarily alter the size, shape, and surface finish of metal by placing a workpiece against a rotating abrasive surface or wheel. Grinding machines may also be used for grinding glass, ceramics, plastics, and rubber. Examples of grinding machines include abrasive belt machines, abrasive cutoff machines, cylindrical grinders, centerless grinders, gear grinders, internal grinders, lapping machines, offhand grinders, surface grinders, swing frame grinders, and thread grinders.

Grinding machine hazards

Amputation injuries occur when the operator’s hands enter the point of operation during the following activities:

§  Grinding on the side of the wheel not designed for grinding.

§  Using an inadequately guarded grinding wheel.

§  Using an incorrectly adjusted or missing work rest or a poorly maintained or unbalanced abrasive wheel.

§  Wedging a tool between the work rest and the abrasive wheel, causing the wheel to break into flying particles.

§  Adjusting the work rest, balancing the wheel, cleaning the area around the abrasive wheel, attempting to stop a rotating abrasive wheel by hand, and loading and unloading parts or measuring parts while the abrasive wheel is still rotating.

Case History

After grinding a piece of steel on an offhand grinder, an employee turned off the machine and tried to stop the wheel with a piece of scrap steel. His hand slipped and hit the rotating abrasive wheel, amputating the tip of his left middle finger.

Grinding machines safeguards

You can help prevent worker accidents and injuries by using guards and other engineering controls. Here are some examples:

§  Install safety guards that cover the spindle end, nut, and flange projections or otherwise ensure adequate operator protection.

§  Install adjustable and rigid work rests on offhand grinding machines.

§  Install guards on foot-operated controls to prevent accidental activation.

§  Instruct operators to use hand tools to maintain a safe distance between the operator and the point of operation when needed.

Work practice and administrative controls

Work practices and administrative controls also are important. Here are some recommended ways to safeguard grinding machines by using the following controls:

§  Develop and implement safe work practices for grinding machine operations and conduct periodic inspections to ensure compliance.

§  Ensure that all operators receive appropriate on-the-job training and supervision until they can work safely on their own.

§  Instruct operators to inspect the grinding wheel to ensure that it is not defective, unbalanced, loose, or too small.

§  Instruct operators to inspect the point of operation guard and to adjust it if necessary prior to each use.

§  Instruct operators to adjust the work rest to within 1/8 inch from the wheel.

§  Instruct employees not to wear gloves, jewelry, or loose-fitting clothing while operating grinding machines and to secure long hair in a net or cap.

§  Instruct employees to keep their hands as far away as possible from the point of operation while feeding work into an offhand grinder.

§  Instruct employees not to adjust the guard or clean the grinding machine while the abrasive wheel is still rotating.

§  Instruct employees to perform servicing and maintenance activities under an energy control program in §1910.147.

Milling machines | Safeguarding for Specific Types of Machinery

Electrically powered milling machines cut metal using a rotating cutting device called a milling cutter. These machines cut flat surfaces, angles, slots, grooves, shoulders, inclined surfaces, dovetails, and recessed cuts. Cutters of different sizes and shapes are available for a wide variety of milling operations.

Milling machines include knee-and-column machines, bed-type or manufacturing machines, and special milling machines designed for special applications. Typical milling operations consist of selecting and installing the appropriate milling cutter, loading a work piece on the milling table, controlling the table movement to feed the part against the rotating milling cutter, and calipering or measuring the part.

Milling machine hazards

The following procedures are frequent causes of amputation from milling machines:

§  Loading or unloading parts and calipering or measuring the milled part while the cutter is still rotating.

§  Performing servicing and maintenance activities such as setting up the machine, changing and lubricating parts, clearing jams, and removing excess oil, chips, fines, turnings, or particles while the milling machine is either stopped but still energized, or while the cutter is still rotating.

§  Getting jewelry or loose-fitting clothing entangled in the rotating cutter.

Case History

An employee was using a milling machine to cut metal samples to length. After a part had been cut, the employee needed to gauge the part size. While he was checking the edge of the sample, the blade caught the tip of his glove, pulled his hand into the cutting area, and amputated his right ring finger and part of his middle finger. Source: OSHA IMIS Accident Investigation Database

Milling machine safeguards

You should implement the following engineering, work practices, and administrative controls:

§  Install self-closing guards that enclose the milling cutter when the table has been withdrawn.

§  Install an interlocked barrier guard around the table. When equipped with a cutter blade brake, the brake should be applied when opening or removing the interlocked barrier guard.

§  Use other safeguarding devices such as splash shields, chip shields, or barriers if they provide effective protection to the operator and when it is impractical to guard cutters without interfering with normal production operations or creating a more hazardous situation.

§  Instruct operators not to use a jib or vise that prevents the point of operation guard from being adjusted appropriately.

§  Develop and implement safe work practices for machine operators and conduct periodic inspections to ensure compliance.

§  Ensure that all operators receive appropriate on-the-job training by experienced operators until they can work safely on their own.

§  Instruct operators to move the work holding device back to a safe distance when loading or unloading parts and calipering or measuring the work and not to perform these activities while the cutter is still rotating unless the cutter is adequately guarded.

§  Prohibit operators from reaching around the cutter or hob to remove chips while the machine is in motion or not de-energized.

§  Instruct operators to remove fines, turnings, or particles only with a brush while the cutter is stopped.

§  Instruct operators to place the jib or vise locking arrangement so that force must be exerted away from the milling cutter.

§  Instruct operators not to leave the cutter exposed after withdrawing work piece.

§  Instruct operators to turn off the milling machine when not in use or when left unattended for any period of time.

§  Instruct employees not to wear gloves, jewelry, or loose-fitting clothing while operating a milling machine and to secure long hair in a net or cap.

§  Instruct operators to perform servicing and maintenance activities under an energy control program in §1910.147.